“We are still not sure what happened. It was totally unexpected,” Rick Snyder said Monday.

Heather, 31, had to have her index and middle finger amputated after the rampage by a lone gunman on July 20, 2012, at a showing of “The Dark Knight Rises” at the Century Aurora 16 movie theater.

“She never totally recovered from it. She was reminded of it every day,” her father said.

Heather was among a group of 12 Red Robin workers who attended the movie to celebrate the 27th birthday of a fellow employee, Alex Sullivan, on the night of the shooting.

Heather and six other members of the party were wounded. Alex was the only one who died.

Alex and 11 others died in the 2012 shooting, and 70 others were injured. The gunman was sentenced to 12 consecutive life sentences in prison, followed by 3,318 years for trying to kill dozens of others and plotting to blow up his apartment. There is no chance for parole.

She testified that the shooting began about 15 minutes after the movie began, and she felt a burning sensation on her left arm and sharp pain in her left leg after the gunman began shooting.

“I was thinking, ‘Oh, my god! What is going on?’ ” she testified. She said she never saw the gunman but heard popping sounds. Heather was taken to Denver Health Medical Center, where she had buckshot removed from her leg, had two fingers amputated and was treated for a gunshot wound to her forearm.

“We were there when she testified to that,” said Tom Sullivan, Alex’s father. “I have a vivid memory of seeing her at Alex’s funeral. It is tough for them. They were Alex’s friends.”

Devin Oehler went to work at the Red Robin on Havana Street in Aurora a year or so after the shootings.

She remembers Heather, who was among the first people she met there, as a kind and fun-loving mentor.

“She taught me everything I needed to know to be a hostess. She had this infectious smile that would light up the room,” Oehler said. “Even when she was slammed, she had a smile on her face. She had a bubbly personality. She had a temper if you got on her bad side, but that didn’t come out too much.”

Heather even helped her plan her wedding when her future husband was in Japan serving in the Marine Corps.

The two never discussed that horrible night, but Oehler said she knew Heather was glad to be alive.

Heather, who lived in Centennial, leaves behind a 3-year-old daughter, her father said.

Just after 5 p.m. Sunday, Arapahoe County Sheriff’s deputies received a call from the 14400 block of East Fremont Avenue reporting that someone was not breathing, according to Julie Brooks, a sheriff’s spokeswoman.

They found a woman named Heather Snyder, 31. “South Metro (Fire Rescue) attempted to revive her, they were unsuccessful,” Brooks said.

The gunfire did not result in any injuries directly, but bullets did strike a car that then crashed. The resulting crash caused injuries for an unknown number of people, spokesman for the Thornton Police Department Jesus Mendez said.